9:42 AM - 10:02 AM
[O05-02] The impact of global warming on the "senjo-kousuitai"
★Invited Papers
Keywords:Senjo-kousuitai, Global Warming, Large ensemble, Downscaling
In recent years, disasters caused by “senjo-kousuitai” have occurred every year in Japan. Whether global warming has an effect on the occurrence of senjo-kousuitai and whether the frequency and intensity of senjo-kousuitai will change with future warming is an important factor in assessing climate change risk and adaptation policies in Japan.
A senjo-kousuitai is relatively small in spatial scale and occurs infrequently. Large-scale ensemble calculations using high-resolution numerical models are required to evaluate such phenomena from a climatological viewpoint. In this study, a large-scale ensemble downscaling experiment was conducted using a regional climate model with a grid spacing of 5 km from the Database for Policy Decision-Making for Future Climate Change (d4PDF) to analyze the effects of global warming on the senjo-kousuitai. The results show that the number of senjo-kousuitai under future climates of 2 and 4 K rise are approximately 1.3 and 1.6 times larger than those under the present climate, respectively. The total precipitation in individual senjo-kousuitai is also projected to increase. The increase in water vapor associated with the rise in temperature is the main reason for this increase. On the other hand, the stabilization of stratification and the decrease in vertical shear may suppress the increase in senjo-kousuitai. Using the same system, we also analyzed the occurrence of senjo-kousuitai in 2023 and found that past warming had increased the probability of occurrence of senjo-kousuitai in 2023.
A senjo-kousuitai is relatively small in spatial scale and occurs infrequently. Large-scale ensemble calculations using high-resolution numerical models are required to evaluate such phenomena from a climatological viewpoint. In this study, a large-scale ensemble downscaling experiment was conducted using a regional climate model with a grid spacing of 5 km from the Database for Policy Decision-Making for Future Climate Change (d4PDF) to analyze the effects of global warming on the senjo-kousuitai. The results show that the number of senjo-kousuitai under future climates of 2 and 4 K rise are approximately 1.3 and 1.6 times larger than those under the present climate, respectively. The total precipitation in individual senjo-kousuitai is also projected to increase. The increase in water vapor associated with the rise in temperature is the main reason for this increase. On the other hand, the stabilization of stratification and the decrease in vertical shear may suppress the increase in senjo-kousuitai. Using the same system, we also analyzed the occurrence of senjo-kousuitai in 2023 and found that past warming had increased the probability of occurrence of senjo-kousuitai in 2023.